Use function to convert indices for text protocol

Use a proper function instead of left/midRef(index).toUtf8().size().

Makes it more clear what is happening and makes it easier when wayland
text protocol switches from byte-based to unicode character-based indices.

Also rename parameters of existing indexFromWayland() function to be the
same as in the new function.

Change-Id: Ie90abdcb264b74a024e96e041d5daf651920e9e4
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>

2 files changed, 15 insertions, 9 deletions

diff --git a/src/shared/qwaylandinputmethodeventbuilder.cpp b/src/shared/qwaylandinputmethodeventbuilder.cpp
index eb527c15a..fe93f5146 100644
--- a/src/shared/qwaylandinputmethodeventbuilder.cpp
+++ b/src/shared/qwaylandinputmethodeventbuilder.cpp
@@ -268,19 +268,24 @@ QWaylandInputMethodContentType QWaylandInputMethodContentType::convert(Qt::Input
     return QWaylandInputMethodContentType{hint, purpose};
 }
 
-int QWaylandInputMethodEventBuilder::indexFromWayland(const QString &str, int utf8Index, int baseIndex)
+int QWaylandInputMethodEventBuilder::indexFromWayland(const QString &text, int length, int base)
 {
-    if (utf8Index == 0)
-        return baseIndex;
+    if (length == 0)
+        return base;
 
-    if (utf8Index < 0) {
-        const QByteArray &utf8 = str.leftRef(baseIndex).toUtf8();
-        return QString::fromUtf8(utf8.left(qMax(utf8.length() + utf8Index, 0))).length();
+    if (length < 0) {
+        const QByteArray &utf8 = text.leftRef(base).toUtf8();
+        return QString::fromUtf8(utf8.left(qMax(utf8.length() + length, 0))).length();
     } else {
-        const QByteArray &utf8 = str.midRef(baseIndex).toUtf8();
-        return QString::fromUtf8(utf8.left(utf8Index)).length() + baseIndex;
+        const QByteArray &utf8 = text.midRef(base).toUtf8();
+        return QString::fromUtf8(utf8.left(length)).length() + base;
     }
 }
 
+int QWaylandInputMethodEventBuilder::indexToWayland(const QString &text, int length, int base)
+{
+    return text.midRef(base, length).toUtf8().size();
+}
+
 QT_END_NAMESPACE
 
diff --git a/src/shared/qwaylandinputmethodeventbuilder.h b/src/shared/qwaylandinputmethodeventbuilder.h
index 188a6a94b..3912afc04 100644
--- a/src/shared/qwaylandinputmethodeventbuilder.h
+++ b/src/shared/qwaylandinputmethodeventbuilder.h
@@ -61,7 +61,8 @@ public:
     QInputMethodEvent buildCommit(const QString &text);
     QInputMethodEvent buildPreedit(const QString &text);
 
-    static int indexFromWayland(const QString &str, int utf8Index, int baseIndex = 0);
+    static int indexFromWayland(const QString &text, int length, int base = 0);
+    static int indexToWayland(const QString &text, int length, int base = 0);
 private:
     QPair<int, int> replacementForDeleteSurrounding();